revised examples

example/double-click.c

@@ -1,14 +1,14 @@
 /*
  *       SCLICK                      SCLICK
- *     _________                 __________
+ *     __________                  ___________
  *     |        |                  |       | |
  *     |        |                  |       | |
- * -----        ------------------       | ------
+ * -----        --------------------       | ------
  *                                         |
- *  TIME_LIMIT                 TIME_LIMIT|
+ *  TIME_LIMIT               TIME_LIMIT    |
- * >---------<               >----------<|
+ * >---------<               >--------<    |        ==> DCLICK_INT
- *      LATENCY       WINDOW             | 
+ *      LATENCY       WINDOW          >----|---<   
- *    >----------<>----------<           | => DCLICK INT
+ *    >----------<>----------<          LATENCY
  * */
 #define _GNU_SOURCE
 #include <stdio.h>
@@ -54,18 +54,20 @@ int main() {
     lis.cfg.filter.mode = LIS3DH_FILTER_MODE_NORMAL;
     lis.cfg.filter.cutoff = LIS3DH_FILTER_CUTOFF_8;
     lis.cfg.filter.click = 1; /* enable filtering for CLICK function */
+
     lis.cfg.click.xd = 1; /* enable X axis double click */
     lis.cfg.click.yd = 1; /* enable Y axis double click */
     lis.cfg.click.zd = 1; /* enable Z axis double click */
+
     lis.cfg.pin1.click = 1; /* enable click int src through pin1 */
     lis.cfg.int1.latch = 1; /* latch interrupt until INT1_SRC is read */
 
     /* 1 LSb = 16 mg @ FS_2G 
-     * so a 0.072g 'shock' is 72/16 = 4.5
+     * so a 0.3g 'shock' is 300/16 = 18.75
-     * However, the device can have up to +- 40mg read error
+     * However, the device can have up to +- 40mg read error, so add 40mg
-     * 0.112g => 112/16 = 15
+     * 0.34g => 340/16 ~= 21
      */
-    lis.cfg.click_ths = 15; /* pretty sensitive */
+    lis.cfg.click_ths = 21; /* pretty sensitive */
 
     /* Duration time is measured in N/ODR where:
      * --- N = The content of the intX_dur integer
@@ -88,6 +90,11 @@ int main() {
         /* error handling */
     }
 
+    /* read CLICK_SRC to clear previous interrupts, if any */
+    if (lis3dh_read_click(&lis)) {
+        /* error handling */
+    }
+
     for(;;) {
 
         /* poll interrupt on INT1 pin */
@@ -100,10 +107,10 @@ int main() {
             /* error handling */
         }
 
-        /* only print data if DCLICK=1 in CLICK_SRC */
+        /* only print if DCLICK=1 */
         if (LIS3DH_CLICK_DCLICK(lis.src.click)) {
             /* print data gathered from CLICK_SRC */
-            printf("Click: X=%d, Y=%d, Z=%d, Sign=%d, S_en=%d, D_en=%d\n",
+            printf("Click: X=%d, Y=%d, Z=%d, Sign=%d, S_CLICK=%d, D_CLICK=%d\n",
                 LIS3DH_CLICK_SRC_X(lis.src.click),
                 LIS3DH_CLICK_SRC_Y(lis.src.click),
                 LIS3DH_CLICK_SRC_Z(lis.src.click),
@@ -111,6 +118,10 @@ int main() {
                 LIS3DH_CLICK_SCLICK(lis.src.click),
                 LIS3DH_CLICK_DCLICK(lis.src.click));
         }
+        
+        /* sleep for 5 ms because gpio sysfs is slow at clearing interrupts */
+        /* not necessary with "real" IRQ */
+        usleep(5000);
     }
     
     /* unregister interrupt */

example/inertial-wakeup.c

@@ -45,7 +45,7 @@ int main() {
 
     /* 1 LSb = 16 mg @ FS_2G 
      * 0.3g threshold = 300/16 = 18.75
-     * add read error, +40mg => 240/16 = 21.25 ~= 21
+     * add read error, +40mg => 340/16 = 21.25 ~= 21
      * if you for some reason don't want to use the HP filter,
      * just add 1g to the threshold calculation.
      */
@@ -72,8 +72,7 @@ int main() {
     lis.cfg.int1.aoi = 0; /* set to 1 for AND mode */
     lis.cfg.int1.en_6d = 0;
     
-
+    /* latch interrupt */
-    /* latch interrupt. might not work. */
     lis.cfg.int1.latch = 1;
 
     /* set up a HP filter to ignore constant earth acceleration */
@@ -81,7 +80,6 @@ int main() {
     lis.cfg.filter.cutoff = LIS3DH_FILTER_CUTOFF_8;
     lis.cfg.filter.ia1 = 1; /* enable filter for INT1 generator */
     
-    
     /* write device config */
     if (lis3dh_configure(&lis)) {
         /* error handling */
@@ -111,13 +109,17 @@ int main() {
 
         /* print received interrupt .. */
         printf("IA=%d ZH=%d ZL=%d YH=%d YL=%d XH=%d XL=%d\n",
-            !!(lis.src.int1 & 0x40),
+            LIS3DH_INT_SRC_IA(lis.src.int1),
             LIS3DH_INT_SRC_Z_HIGH(lis.src.int1),
             LIS3DH_INT_SRC_Z_LOW(lis.src.int1),
             LIS3DH_INT_SRC_Y_HIGH(lis.src.int1),
             LIS3DH_INT_SRC_Y_LOW(lis.src.int1),
             LIS3DH_INT_SRC_X_HIGH(lis.src.int1),
             LIS3DH_INT_SRC_X_LOW(lis.src.int1));
+
+        /* sleep for 5 ms because gpio sysfs is slow at clearing interrupts */
+        /* not necessary with "real" IRQ */
+        usleep(5000);
     }
     
     /* unregister interrupt */

lis3dh.c

@@ -199,6 +199,7 @@ int lis3dh_configure(lis3dh_t *lis3dh) {
     err |= lis3dh->dev.write(REG_ACT_THS, act_ths);
     err |= lis3dh->dev.write(REG_ACT_DUR, lis3dh->cfg.act_dur);
     err |= lis3dh->dev.write(REG_TEMP_CFG_REG, temp_cfg_reg);
+    err |= lis3dh->dev.write(REG_REFERENCE, lis3dh->cfg.reference);
 
     err |= lis3dh->dev.write(REG_CTRL_REG0, ctrl_reg0);
     err |= lis3dh->dev.write(REG_CTRL_REG1, ctrl_reg1);
@@ -287,6 +288,7 @@ int lis3dh_read(lis3dh_t *lis3dh) {
     return err;
 }
 
+/* assume fifo has been configured and poll'd */
 int lis3dh_read_fifo(lis3dh_t *lis3dh, struct lis3dh_fifo_data *fifo) {
     int32_t x, y, z;
     uint8_t scale, sens;

lis3dh.h

@@ -4,20 +4,21 @@
 #include <stdint.h>
 
 /* macros for checking INT_SRC registers upon interrupt */
-#define LIS3DH_INT_SRC_X_LOW(c)  ((c & 1) == 1)
+#define LIS3DH_INT_SRC_X_LOW(c)   (!!(c & 0x01)) /* X axis low */
-#define LIS3DH_INT_SRC_X_HIGH(c) (((c >> 1) & 1) == 1)
+#define LIS3DH_INT_SRC_X_HIGH(c)  (!!(c & 0x02)) /* X axis high */
-#define LIS3DH_INT_SRC_Y_LOW(c)  (((c >> 2) & 1) == 1)
+#define LIS3DH_INT_SRC_Y_LOW(c)   (!!(c & 0x04)) /* Y axis low */
-#define LIS3DH_INT_SRC_Y_HIGH(c) (((c >> 3) & 1) == 1)
+#define LIS3DH_INT_SRC_Y_HIGH(c)  (!!(c & 0x08)) /* Y axis high */
-#define LIS3DH_INT_SRC_Z_LOW(c)  (((c >> 4) & 1) == 1)
+#define LIS3DH_INT_SRC_Z_LOW(c)   (!!(c & 0x10)) /* Z axis low */
-#define LIS3DH_INT_SRC_Z_HIGH(c) (((c >> 5) & 1) == 1)
+#define LIS3DH_INT_SRC_Z_HIGH(c)  (!!(c & 0x20)) /* Z axis high */
+#define LIS3DH_INT_SRC_IA(c)      (!!(c & 0x40)) /* Interrupt active */
 
 /* macros for checking CLICK_SRC register upon interrupt */
-#define LIS3DH_CLICK_SRC_X(c)    ((c & 1) == 1)        /* X high event */
+#define LIS3DH_CLICK_SRC_X(c)     (!!(c & 0x01)) /* X high event */
-#define LIS3DH_CLICK_SRC_Y(c)    (((c >> 1) & 1) == 1) /* Y high event */
+#define LIS3DH_CLICK_SRC_Y(c)     (!!(c & 0x02)) /* Y high event */
-#define LIS3DH_CLICK_SRC_Z(c)    (((c >> 2) & 1) == 1) /* Z high event */
+#define LIS3DH_CLICK_SRC_Z(c)     (!!(c & 0x04)) /* Z high event */
-#define LIS3DH_CLICK_SIGN(c)     (((c >> 3) & 1) == 1) /* Click sign, 1 = positive */
+#define LIS3DH_CLICK_SIGN(c)      (!!(c & 0x08)) /* Click sign, 1 = positive */
-#define LIS3DH_CLICK_SCLICK(c)   (((c >> 4) & 1) == 1) /* Single-click det. enabled */
+#define LIS3DH_CLICK_SCLICK(c)    (!!(c & 0x10)) /* Single-click det. enabled */
-#define LIS3DH_CLICK_DCLICK(c)   (((c >> 5) & 1) == 1) /* Double-click det. enabled */
+#define LIS3DH_CLICK_DCLICK(c)    (!!(c & 0x20)) /* Double-click det. enabled */
 
 /* rates */
 /* all power modes */
@@ -126,7 +127,7 @@ struct lis3dh_int_config {
     uint8_t latch; /* active until INT1_SRC/INT2_SRC is read */
 };
 
-/* config for INT2 trigger output */
+/* config for interrupt output pin #2 */
 struct lis3dh_int_pin2_config {
     uint8_t click; /* CLICK interrupt */
     uint8_t ia1; /* IA1 interrupt */
@@ -136,7 +137,7 @@ struct lis3dh_int_pin2_config {
     uint8_t polarity; /* INT1 & INT2 polarity. 0 active high, 1 active low */
 };
 
-/* config for INT1 trigger output */
+/* config for interrupt output pin #1 */
 struct lis3dh_int_pin1_config {
     uint8_t click; /* CLICK interrupt */
     uint8_t ia1; /* IA1 interrupt */
@@ -221,6 +222,8 @@ struct lis3dh_config {
     uint8_t sdo_pullup; /* Use pull-up on SDO. default 0 use */
     uint8_t en_adc; /* enable ADC */
     uint8_t en_temp; /* enable temp sensor on ADC 3 */
+
+    uint8_t reference; /* HP filter reference */
 };
 
 /* reads from internal ADCs. 

main.c

@@ -118,13 +118,17 @@ int main() {
 
         /* print received interrupt .. */
         printf("IA=%d ZH=%d ZL=%d YH=%d YL=%d XH=%d XL=%d\n",
-            !!(lis.src.int1 & 0x40), 
+            LIS3DH_INT_SRC_IA(lis.src.int1), 
             LIS3DH_INT_SRC_Z_HIGH(lis.src.int1),
             LIS3DH_INT_SRC_Z_LOW(lis.src.int1),
             LIS3DH_INT_SRC_Y_HIGH(lis.src.int1),
             LIS3DH_INT_SRC_Y_LOW(lis.src.int1),
             LIS3DH_INT_SRC_X_HIGH(lis.src.int1),
             LIS3DH_INT_SRC_X_LOW(lis.src.int1));
+
+        /* sleep for 5 ms because gpio sysfs is slow at clearing interrupts */
+        /* not necessary with "real" IRQ */
+        usleep(5000);
     }
     
     /* unregister interrupt */